KR20220082559A - Display device, data driving circuit and display driving method - Google Patents

Abstract

Embodiments of the present invention relate to a display device, a data driving circuit, and a driving method of the display device, and more particularly, to realize high luminance by using a voltage sensing method when compensating for characteristics of a light emitting device in a sub-pixel while increasing an aperture area; A display device capable of reducing cost, a data driving circuit, and a display device driving method may be provided.

Description

Display device, data driving circuit, and display device driving method

SUMMARY Embodiments of the present invention relate to a display device, a data driving circuit, and a display device driving method.

Recently, an organic light emitting display device, which has been spotlighted as a display device, has advantages such as fast response speed, luminous efficiency, luminance, and viewing angle by using an organic light emitting diode (OLED) that emits light by itself.

The driving transistor in each sub-pixel of the organic light emitting diode display may be degraded as the driving time increases, and thus characteristic values such as threshold voltage and mobility may change.

In addition, the organic light emitting diode also deteriorates as the driving time increases, so characteristic values such as threshold voltage may change, and since the degree of deterioration between the organic light emitting diodes may be different, the deviation of the characteristic values between the organic light emitting diodes in each sub-pixel may be can occur

Accordingly, there is a need for a method of compensating a characteristic value between driving transistors and compensating a characteristic value due to deterioration of an organic light emitting diode.

Embodiments of the present invention may provide a display device capable of sensing a change in a characteristic value of a light emitting device in a sub-pixel, a data driving circuit, and a display device driving method.

Embodiments of the present invention may provide a display device, a data driving circuit, and a display device driving method capable of sensing deterioration of a light emitting device by sensing a voltage applied to a sensing line under a one-scan structure.

Embodiments of the present invention may provide a display device, a data driving circuit, and a display device driving method having a high aperture ratio and reducing the cost of the data driving circuit.

According to the exemplary embodiments of the present invention, in a display device, a display panel including a plurality of data lines, a plurality of gate lines and a plurality of sub-pixels including a light emitting device, and a data driving circuit for driving the plurality of data lines , and a gate driving circuit driving the plurality of gate lines, wherein each of the plurality of sub-pixels is controlled by a driving transistor driving the light emitting device and a gate signal, and includes a first node of the driving transistor and A switching transistor controlling a connection between the corresponding data lines, a sensing transistor controlled by the gate signal and controlling a connection between the second node of the driving transistor and the corresponding sensing line, and a first node and a second node of the driving transistor a storage capacitor electrically connected therebetween; A second switch for supplying a driving reference voltage, an analog-to-digital converter for sensing the voltage of the sensing line, and a third switch for controlling an electrical connection between the sensing line and the analog-to-digital converter, wherein the third switch When the first switch is in a turn-on state, a sensing driving data voltage is applied to the first node, and when the first switch is in the turn-off state, the voltage of the first node fluctuates, and the second switch When is in a turn-on state, a sensing driving reference voltage is applied to the second node, and when the second switch is in a turn-off state, the voltage of the second node varies, and the first switch and the In a period in which the second switch is turned off and the voltage of the first node is increased, the third switch is turned on, and the analog-to-digital converter provides a display device that senses the voltage of the sensing line. can

In embodiments of the present invention, during a first period, the first switch and the second switch are turned on, a data voltage for sensing driving is applied to the first node, and a reference for driving sensing to the second node. A display device to which a voltage is applied may be provided.

In embodiments of the present invention, during a second period after the first period, the first switch maintains a turned-on state, the second switch is turned off, and a data voltage for sensing driving is applied to the first node. is applied, and the second node may provide a display device in which a voltage rises.

In embodiments of the present invention, during a third period after the second period, the first switch is turned off, the second switch maintains a turned-off state, and each of the first node and the second node is simultaneously decreased, and during a fourth period after the third period, the first switch maintains a turned-off state, the second switch is turned on, and the sensing driving reference voltage is set to the second is applied again to the node, the voltage of the first node changes by the amount of voltage fluctuation of the second node, the first switch maintains a turn-off state during a fifth period after the fourth period, and the second node It is possible to provide a display device in which a switch is turned off and voltages of the first node and the second node increase at the same time.

In embodiments of the present invention, after the fifth period, the third switch may be turned on and the analog-to-digital converter may provide a display device that senses the voltage of the sensing line.

In the embodiments of the present invention, from the point in time when the gate signal of the turn-on level voltage period is applied to the switching transistor and the sensing transistor, the gate signal of the turn-off level voltage period is applied to the switching transistor and the sensing transistor. In the period before, the data voltage for sensing driving is applied to the first node, the voltage of the first node is changed, the reference voltage for driving sensing is applied to the second node, or the voltage of the second node is It is possible to provide a variable display device.

Embodiments of the present invention further include a line capacitor electrically connected to the sensing line, wherein a reference voltage for sensing driving is applied to the second node again, and the line capacitor is the first switch and the second switch It is possible to provide a display device that is charged during a period in which is in a turn-off state.

A method of driving a display device according to an embodiment of the present invention is the method of driving a display device, wherein the display device includes a plurality of data lines, a plurality of gate lines, and a plurality of sub-pixels including a light emitting device. a display panel comprising: a display panel, a data driving circuit driving the plurality of data lines, and a gate driving circuit driving the plurality of gate lines, wherein each of the plurality of sub-pixels includes a driving transistor driving the light emitting device; A switching transistor controlled by a gate signal and controlling a connection between a first node of the driving transistor and a corresponding data line, controlled by the gate signal, and controlling a connection between a second node of the driving transistor and a corresponding sensing line a sensing transistor and a storage capacitor electrically connected between a first node and a second node of the driving transistor, wherein the display device includes a data voltage output node from which a data voltage in the data driving circuit is output and the data line A first switch for controlling a connection, a second switch for supplying a reference voltage for sensing driving to the second node, an analog-to-digital converter for sensing the voltage of the sensing line, and electricity between the sensing line and the analog-to-digital converter and a third switch for controlling an external connection, wherein when the first switch is in a turn-on state, a sensing driving data voltage is applied to the first node, and when the first switch is in a turn-off state , the voltage of the first node varies, and when the second switch is in a turn-on state, a sensing driving reference voltage is applied to the second node, and when the second switch is in a turn-off state, the The voltage of the second node is changed, the first switch and the second switch are in a turned-off state, and in a period in which the voltage of the first node is increased, the third switch is turned on, the analog digital In the method of driving a display device in which a converter senses the voltage of the sensing line, the driving of the display device includes: the first switch Q and the second switch are turned on, a data voltage for sensing driving is applied to the first node, and a reference voltage for driving sensing is applied to the second node, wherein the first switch is turned on maintain, the second switch is turned off, a sensing driving data voltage is applied to the first node, and the voltage of the second node is increased, the first switch is turned off, and the The second switch maintains the turn-off state, the voltages of the first node and the second node are lowered, the first switch maintains the turn-off state, and the second switch is turned on , applying a sensing driving reference voltage to the second node again, the first switch maintains a turned-off state, the second switch is turned off, and the voltage of the first node and the second The method may include simultaneously increasing a voltage of a node, turning on the third switch and sensing the voltage of the sensing line by the analog-to-digital converter.

In embodiments of the present invention, in a period in which a gate signal of a turn-on level voltage section is applied to the switching transistor and the sensing transistor, the third switch is turned on, and the analog-to-digital converter is the voltage of the sensing line A method of driving a display device that senses

A data driving circuit according to embodiments of the present invention includes a data voltage output unit for outputting a data voltage to a data line, a reference voltage output unit for outputting a reference voltage for sensing driving to a sensing line, and a sensing line connected to the sensing line A voltage sensing unit sensing a line voltage, a first switch connected to a data voltage output node of a data voltage output unit to control an output of a data voltage for sensing driving to the data line, and a reference voltage for sensing driving of the reference voltage output unit a second switch connected to an output node to control an output of the sensing driving reference voltage, and connected to a voltage input node of the voltage sensing unit to control an input of a voltage of the sensing line to the voltage sensing unit A first period including three switches, wherein the first switch is turned on to output a sensing driving data voltage, and the second switch is turned on to output a sensing driving reference voltage, after the first period In a second period in which the first switch maintains a turn-on state, a sensing driving data voltage is output, and the second switch is turned off, after the second period, the first switch is turned off A third period in which the second switch maintains a turn-off state, and after the third period, the first switch maintains a turn-off state and the second switch is turned on to output a sensing driving reference voltage a fourth period in which the first switch maintains a turn-off state and the second switch maintains a turn-off state after the fourth period, a fifth period in which the third switch remains in the turn-off state, after the fifth period When turned on, the voltage sensing unit may provide a data driving circuit that receives the voltage of the sensing line.

In embodiments of the present invention, the data driving circuit is electrically connected to a controller that controls the first switch, the second switch, and the third switch, and the first switch, the second switch, and the third switch The timing at which the switch is turned on and turned off may provide a data driving circuit controlled by a control signal output from the controller. A display device according to an embodiment of the present invention includes a display panel including a plurality of data lines, a plurality of scan lines, and a plurality of sub-pixels including a light emitting device, and a data driving circuit for driving the plurality of data lines , and a gate driving circuit driving the plurality of gate lines, wherein each of the plurality of sub-pixels is controlled by a driving transistor driving the light emitting device and a gate signal, and includes a first node of the driving transistor and A switching transistor controlling a connection between the corresponding data lines, a sensing transistor controlled by the gate signal and controlling a connection between the second node of the driving transistor and the corresponding sensing line, and a first node and a second node of the driving transistor a storage capacitor electrically connected between a voltage fluctuates, and when the impedance of the data line is greater than or equal to a predefined threshold, the data line is in the high-impedance state; when the impedance of the data line is less than the threshold, the data line is in the low-impedance state; When the sensing driving reference voltage is supplied to the sensing line, the sensing driving reference voltage is applied to the second node, and when the supply of the sensing driving reference voltage to the sensing line is cut off, the second node A display device in which a voltage varies, a period in which the data line is in a low impedance state includes a period in which the light emitting element emits light, and a period in which the data line is in a high impedance state includes a period in which the light emitting element does not emit light. can provide

According to embodiments of the present invention, it is possible to provide a display device capable of sensing a change in a characteristic value of a light emitting device in a sub-pixel, a data driving circuit, and a display device driving method.

According to embodiments of the present invention, it is possible to provide a display device, a data driving circuit, and a display device driving method capable of sensing deterioration of a light emitting device by sensing a voltage applied to a sensing line under a one-scan structure.

According to embodiments of the present invention, it is possible to provide a display device, a data driving circuit, and a display device driving method having a high aperture ratio and reducing the cost of the data driving circuit.

1 is a system configuration diagram of a display device according to embodiments of the present invention.
2 is an exemplary diagram of a sub-pixel structure according to embodiments of the present invention.
3 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform for each period in sensing driving according to embodiments of the present invention.
4 is a diagram illustrating an exemplary sub-pixel structure and waveforms of control signals and voltages according to embodiments of the present invention in an initialization period.
5 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention during a tracking period.
6 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a first sensing period.
7 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a second sensing period.
8 is a diagram illustrating an exemplary sub-pixel structure and control signals and voltage waveforms according to embodiments of the present invention in a third sensing period.
9 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a fourth sensing period.
10 is an exemplary diagram of a data driving circuit structure according to embodiments of the present invention.
11 is a diagram illustrating a sensing operation step by step according to embodiments of the present invention.
12 is a diagram illustrating control signals and voltage waveforms for each period for sensing the degree of deterioration of an organic light emitting diode according to embodiments of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted. When "includes", "having", "consisting of", etc. mentioned in this specification are used, other parts may be added unless "only" is used. When a component is expressed in the singular, it may include a case in which the plural is included unless otherwise explicitly stated.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms.

In the description of the positional relationship of the components, when it is described that two or more components are "connected", "coupled" or "connected", two or more components are directly "connected", "coupled" or "connected" ", but it will be understood that two or more components and other components may be further "interposed" and "connected," "coupled," or "connected." Here, other components may be included in one or more of two or more components that are “connected”, “coupled” or “connected” to each other.

In the description of the temporal flow relationship related to the components, the operation method or the production method, for example, the temporal precedence relationship such as "after", "after", "after", "before", etc. Alternatively, when a flow precedence relationship is described, it may include a case where it is not continuous unless "immediately" or "directly" is used.

On the other hand, when numerical values or corresponding information (eg, level, etc.) for a component are mentioned, even if there is no separate explicit description, the numerical value or the corresponding information is based on various factors (eg, process factors, internal or external shock, Noise, etc.) may be interpreted as including an error range that may occur.

1 is a system configuration diagram of a display device 100 according to embodiments of the present invention.

Referring to FIG. 1 , a display device 100 according to example embodiments may include a display panel 110 and a driving circuit for driving the display panel 110 .

The driving circuit may include a data driving circuit 120 and a gate driving circuit 130 , and may further include a timing controller 140 controlling the data driving circuit 120 and the gate driving circuit 130 . .

The display panel 110 may include a substrate SUB and signal lines such as a plurality of data lines DL and a plurality of gate lines GL disposed on the substrate SUB. The display panel 110 may include a plurality of sub-pixels SP connected to a plurality of data lines DL and a plurality of gate lines GL.

The display panel 110 may include an area AA in which an image is displayed and a non-display area NA in which an image is not displayed. In the display panel 110 , a plurality of sub-pixels SP for displaying an image are disposed in the display area AA, and the driving circuits 120 , 130 , and 140 are electrically connected to the non-display area NA. The connected or driving circuits 120 , 130 , 140 may be mounted, and a pad unit to which an integrated circuit or a printed circuit is connected may be disposed.

The data driving circuit 120 is a circuit for driving the plurality of data lines DL, and may supply data signals to the plurality of data lines DL. The gate driving circuit 130 is a circuit for driving the plurality of gate lines GL, and may supply gate signals to the plurality of gate lines GL. The controller 140 may supply the data driving timing control signal DCS to the data driving circuit 120 to control the operation timing of the data driving circuit 120 . The controller may supply the gate driving timing control signal GCS for controlling the operation timing of the gate driving circuit 130 to the gate driving circuit 130 .

The controller 140 starts scanning according to the timing implemented in each frame, and converts the input image data input from the outside according to the data signal format used by the data driving circuit 120 to convert the converted image data (Data) may be supplied to the data driving circuit 120 and data driving may be controlled at an appropriate time according to the scan.

The controller 140 includes various timing signals including a vertical synchronization signal VSYNC, a horizontal synchronization signal HSYNC, an input data enable signal DE, and a clock signal CLK, along with input image data. are received from the outside (eg, a host system (not shown)).

The controller 140 controls the data driving circuit 120 and the gate driving circuit 130 , a vertical synchronization signal VSYNC, a horizontal synchronization signal HSYNC, an input data enable signal DE, and a clock signal ( CLK), and the like, generate various control signals DCS and GCS, and output them to the data driving circuit 120 and the gate driving circuit 130 .

For example, the controller 140 controls the gate driving circuit 130 , a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). : Outputs various gate driving timing control signals (GCS) including Gate Output Enalbe and the like.

In addition, in order to control the data driving circuit 120 , the controller 140 includes various data driving timing control signals including a source start pulse (SSP), a source sampling clock (SSC), and the like. (DCS: Data Driving Timing Control Signal) is output.

The controller 140 may be implemented as a separate component from the data driving circuit 120 , or may be integrated with the data driving circuit 120 and implemented as an integrated circuit.

The data driving circuit 120 drives the plurality of data lines DL by receiving image data Data from the controller 140 and supplying data signals to the plurality of data lines DL. Here, the data driving circuit 120 is also referred to as a source driving circuit.

The data driving circuit 120 may include one or more source driver integrated circuits (SDICs).

Each source driver integrated circuit SDIC may include a shift register, a latch circuit, a digital to analog converter (DAC), an output buffer, and the like. Each source driver integrated circuit SDIC may further include an analog-to-digital converter (ADC) in some cases.

For example, each source driver integrated circuit (SDIC) is connected to the display panel 110 by a tape automated bonding (TAB) method, or is connected to a chip on glass (COG) or a chip on panel (COG). It may be connected to a bonding pad of the display panel 110 in a Chip On Panel (COP) method, or may be implemented in a Chip On Film (COF) method to be connected to the display panel 110 .

The gate driving circuit 130 may output a gate signal of a turn-on level voltage or a gate signal of a turn-off level voltage according to the control of the controller 140 .

The gate driving circuit 130 may sequentially drive the plurality of gate lines GL by sequentially supplying a gate signal of a turn-on level voltage to the plurality of gate lines GL.

The gate driving circuit 130 is connected to the display panel 110 by a tape automatic bonding (TAB) method or bonding pads of the display panel 110 by a chip-on-glass (COG) or chip-on-panel (COP) method. Pad) or may be connected to the display panel 110 according to a chip-on-film (COF) method. Alternatively, the gate driving circuit 130 may be formed in the non-display area NA of the display panel 110 in a gate in panel (GIP) type. The gate driving circuit 130 may be disposed on or connected to the substrate SUB. That is, in the case of the GIP type, the gate driving circuit 130 may be disposed in the non-display area NA of the substrate SUB. The gate driving circuit 130 may be connected to the substrate SUB only in a chip-on-glass (COG) type, a chip-on-film (COF) type, or the like.

The data driving circuit 120 may be connected to one side (eg, an upper side or a lower side) of the display panel 110 . Depending on the driving method, the panel design method, etc., the data driving circuit 120 may be connected to both sides (eg, upper and lower sides) of the display panel 110 or to at least two of the four sides of the display panel 110 . may be

The gate driving circuit 130 may be connected to one side (eg, left or right) of the display panel 110 . Depending on the driving method, the panel design method, etc., the gate driving circuit 130 may be connected to both sides (eg, left and right) of the display panel 110 , or may be connected to at least two of the four sides of the display panel 110 . may be

The controller 140 may be a timing controller used in a conventional display technology or a control device capable of further performing other control functions including the timing controller, and may be a control device different from the timing controller. It may also be a circuit in the control device. The controller 140 may be mounted on a printed circuit board, a flexible printed circuit, or the like, and may be electrically connected to the data driving circuit 120 and the gate driving circuit 130 through the printed circuit board or the flexible printed circuit.

Each of the sub-pixels SP positioned in the display device 100 according to the present exemplary embodiments may include, for example, circuit elements such as a light emitting diode (ED), two or more transistors, and at least one capacitor. have.

The type and number of circuit elements constituting each sub-pixel SP may be variously determined according to a provided function and a design method.

2 is an exemplary diagram of a sub-pixel (SP) structure according to embodiments of the present invention.

Referring to FIG. 2 , each of the plurality of sub-pixels SP disposed on the display panel 110 of the display device 100 according to embodiments of the present invention includes a light emitting device ED and a driving transistor (DRT). ), a switching transistor (SWT), a sensing transistor (SENT), a storage capacitor (Cst), and the like.

Referring to FIG. 2 , the display device 100 according to the embodiments of the present invention includes chairs such as an organic light emitting diode (OLED) display, a quantum dot display, and a micro light emitting diode (LED) display. It may be a light emitting display.

When the display device 100 according to the embodiments of the present invention is an OLED display, each sub-pixel SP may include an organic light emitting diode (OLED) emitting light as a light emitting device ED. When the display device 100 according to the embodiments of the present invention is a quantum dot display, each sub-pixel SP may include a light emitting device ED made of quantum dots, which are semiconductor crystals that emit light by themselves. can When the display device 100 according to embodiments of the present invention is a micro LED display, each sub-pixel SP emits light by itself and uses a micro LED (Micro Light Emitting Diode) made from an inorganic material as a light emitting device (ED). can be included as

Referring to FIG. 2 , the driving transistor DRT is a transistor that supplies a driving current to the light emitting device ED to drive the light emitting device ED, and a driving voltage line DVL that supplies a driving voltage EVDD. and the first electrode of the light emitting device ED may be electrically connected.

The driving transistor DRT may include a first node N1 , a second node N2 , and the like.

In addition, the first node N1 of the driving transistor DRT may be a gate node of the driving transistor DRT, and may be electrically connected to a source node or a drain node of the switching transistor SWT.

The second node N2 of the driving transistor DRT may be a source node or a drain node of the driving transistor DRT, and may be electrically connected to a source node or a drain node of the sensing transistor SENT.

For example, the first electrode of the light emitting device ED is connected to a second node N2 (eg, a source node or a drain node) of the driving transistor DRT, and the second electrode of the light emitting device ED has a base voltage (EVSS) may be authorized.

The switching transistor SWT is controlled by a scan pulse SCAN, which is a type of a gate signal, and may be connected between the first node N1 of the driving transistor DRT and the data line DL. In other words, the switching transistor SWT is turned on or turned off according to the scan pulse SCAN supplied from the scan line SCL, which is a type of the gate line GL, and is driven with the data line DL. A connection between the first node N1 of the transistor DRT may be controlled.

The switching transistor SWT is turned on by the scan pulse SCAN having a turn-on level voltage to transmit the data signal Vdata supplied from the data line DL to the first node N1 of the driving transistor. can deliver

Here, when the switching transistor SWT is an n-type transistor, the turn-on level voltage of the scan pulse SCAN may be a high level voltage. When the switching transistor SWT is a p-type transistor, the turn-on level voltage of the scan pulse SCAN may be a low level voltage.

The storage capacitor Cst may be connected between the first node N1 and the second node N2 of the driving transistor DRT. The storage capacitor Cst is charged with an amount of charge corresponding to the voltage difference between both ends, and during a predetermined frame time, the corresponding sub-pixel SP may emit light.

Referring to FIG. 2 , each of the plurality of sub-pixels SP disposed on the display panel 110 of the display device 100 according to example embodiments may further include a sensing transistor SENT.

The sensing transistor SENT is controlled by a sense pulse SENSE, which is a type of a gate signal, and may be connected between the second node N2 of the driving transistor DRT and the reference voltage line RVL.

Referring to FIG. 2 , the reference voltage line RVL may be a sensing line SL.

Meanwhile, unlike FIG. 2 , the sensing transistor SENT is turned on or off according to the sense pulse SENSE supplied from the sense line SENL, which is a type of the gate line GL, and the sensing line ( SL) and the second node N2 of the driving transistor DRT may be controlled. That is, the first gate line GL1 controlling the switching transistor SWT and the second gate line GL2 controlling the sensing transistor SENT are disposed to drive one sub-pixel SP. A line may be placed. Such a structure may be referred to as a two-scan structure, as will be described below.

The sensing transistor SENT is turned on by a sense pulse SENSE having a turn-on level voltage, and applies the reference voltage VpreS supplied to the sensing line SL to the second node ( N2) can be forwarded.

In addition, the sensing transistor SENT is turned on by the sense pulse SENSE having a turn-on level voltage, and transmits the voltage of the second node N2 of the driving transistor DRT to the sensing line SL. can do it

Referring to FIG. 2 , in the display device 100 according to embodiments of the present invention, a line capacitor Cline may be formed on a sensing line SL. The line capacitor Cline may be charged with a voltage applied to the sensing line SL.

Referring to FIG. 2 , a sensing driving reference voltage VpreS may be applied to the sensing line SL, which may be controlled by a sensing driving switch Spre.

And, referring to FIG. 2 , the sensing line SL may be connected to a sampling switch SAM for controlling voltage sensing of the sensing line SL, and when the sampling switch SAM is turned on, the sensing line SL A voltage of may be applied to an analog-to-digital converter (ADC).

Meanwhile, when the sensing transistor SENT is an n-type transistor, the turn-on level voltage of the sense pulse SENSE may be a high level voltage. When the sensing transistor SENT is a p-type transistor, the turn-on level voltage of the sense pulse SENSE may be a low level voltage.

Here, the function in which the sensing transistor SENT transfers the voltage of the second node N2 of the driving transistor DRT to the sensing line SL may be used during driving to sense the characteristic value of the sub-pixel SP. . In this case, the voltage transferred to the sensing line SL may be a voltage for calculating the characteristic value of the sub-pixel SP or a voltage to which the characteristic value of the sub-pixel SP is reflected.

In the present invention, the characteristic value of the sub-pixel SP may include the threshold voltage and mobility of the driving transistor DRT, and the threshold voltage of the light emitting device ED.

The driving transistor DRT, the switching transistor SWT, and the sensing transistor SENT may be an n-type transistor or a p-type transistor. In embodiments of the present invention, for convenience of description, each of the driving transistor DRT, the switching transistor SWT, and the sensing transistor SENT is an n-type example.

It is also possible to use two different gate lines GL to control the switching transistor SWT and the sensing transistor SENT.

That is, the first gate line GL1 may be used to control the switching transistor SWT and the second gate line GL2 may be used to control the sensing transistor SENT. Such a structure may be referred to as a two-scan structure.

A scan signal SCAN for controlling the switching transistor SWT is output to the first gate line GL1 , and a sense pulse SENSE is outputted to control the sensing transistor SENT to the second gate line GL2 . can be

In such a two-scan structure, a constant voltage may be applied to the gate node N1 of the driving transistor DRT in order to sense the characteristic value of the light emitting device ED, and the source node N2 may be made floating. Since the saturation voltage of the source node N2 varies according to the degree of deterioration of the light emitting device ED, a difference may also occur in the voltage applied to the sensing line SL.

Accordingly, in the two-scan structure, a voltage sensing method of sensing the degree of deterioration of the light emitting device ED by sensing the voltage applied to the sensing line SL may be used.

However, in this case, compared with the case in which two gate lines GL1 and GL2 are respectively disposed in one sub-pixel SP and one gate line GL is disposed to drive one sub-pixel SP Accordingly, there is a problem in that the opening area through which the light emitted from the light emitting device ED can be emitted to the upper surface is reduced.

Meanwhile, referring to FIG. 2 , one gate line GL may be disposed to control the switching transistor SWT and the sensing transistor SENT.

That is, each gate node of the switching transistor SWT and the sensing transistor SENT may be electrically connected to one gate line GL. Accordingly, both the switching transistor SWT and the sensing transistor SENT may be controlled by the turn-on level voltage and the turn-off level voltage of the gate signal applied to one gate line GL. Such a structure may be referred to as a one-scan structure.

Compared to the two-scan structure, the 1-scan structure may increase the opening area as the number of required gate lines GL is reduced. Accordingly, there may be an advantage in terms of luminance.

In such a one-scan structure, the switching transistor SWT and the sensing transistor SENT are connected to one gate line GL, and when a turn-on level voltage is applied to the gate line GL, the switching transistor SWT and the All of the sensing transistors SENT are turned on, and when a turn-off level voltage is applied, both the switching transistor SWT and the sensing transistor SENT are turned off.

Therefore, in the one scan structure, in order to sense the degree of deterioration of the light emitting device ED, it is limited to apply a constant voltage to the gate node N1 of the driving transistor DRT and to make the source node N2 in a floating state. can

Accordingly, in the one-scan structure, the saturation voltage of the source node N2 of the driving transistor DRT does not change according to the degree of deterioration of the light emitting element ED, and thus a voltage sensing method used in the two-scan structure may be limited. Accordingly, in the one-scan structure, the degree of deterioration of the light emitting element ED can be known by measuring a current according to the amount of charge charged in the parasitic capacitor (not shown) of the light emitting element ED.

On the other hand, the difference in the amount of charge charged in the parasitic capacitor (not shown) is very small depending on the degree of deterioration of the light emitting device ED, and an integrator (not shown) capable of converting this into a voltage value is additionally disposed. An integrator (not shown) may be disposed in the data driving circuit 120 .

However, when an integrator (not shown) is additionally disposed in the data driving circuit 120 , there may be problems in that the price of the data driving circuit 120 increases and the size of the data driving circuit 120 increases.

Accordingly, a method capable of sensing the threshold voltage of the light emitting device ED while increasing the opening area has been required.

3 is a diagram illustrating an exemplary structure of a sub-pixel (SP) and a control signal and voltage waveform for each period in sensing driving according to embodiments of the present invention.

Referring to the exemplary diagram of the structure of the sub-pixel SP of FIG. 3 , it is connected to an output node of the data line DL and the data voltage Vdata to control the data voltage Vdata to be applied to the data line DL. A data line switch SWDL may be disposed.

Meanwhile, the display device 100 according to embodiments of the present invention may output a switch control signal Data_Hi-z for controlling turn-on and turn-off of the data line switch SWDL.

Referring to FIG. 3 , when the data line switch SWDL is in a turn-on state, the data line switch SWDL is expressed in a high level state or a low level state, and when the data line switch SWDL is in the turn-off state, data The line switch SWDL may be expressed as a low level state or a high level state. Hereinafter, for convenience of description, it is assumed that the data line switch SWDL is expressed as a high level state when it is turned on and a low level state when it is turned off.

Referring to FIG. 3 , when the data line switch SWDL is turned on, a sensing driving data voltage may be applied to the data line DL, and the state of the data line DL may be defined as a low impedance state. have.

In addition, when the data line switch SWDL is turned off, the data voltage for sensing driving is not applied to the data line DL, and the state of the data line DL may be defined as a high impedance state.

Alternatively, the low impedance state and the high impedance state of the data line DL may be divided based on an impedance of a threshold value at which the impedance of the data line DL is preset. For example, when the impedance of the data line DL is less than the impedance of the preset threshold, the data line DL may be in a low impedance state, and the impedance of the data line DL is greater than the impedance of the preset threshold. In this case, the data line DL may be in a high impedance state.

Referring to FIG. 3 , when the switch control signal Data_Hi-z is at a low level or a high level, the data line switch SWDL may maintain a turn-on state. Also, when the switch control signal Data_Hi-z is at a high level or a low level, the data line switch SWDL may maintain a turn-off state. Hereinafter, for convenience of description, when the switch control signal Data_Hi-z is at a low level, the data line switch SWDL is maintained in a turn-on state, and when the switch control signal Data_Hi-z is at a high level, It is assumed that the data line switch SWDL is maintained in a turned-off state.

The switch control signal Data_Hi-z may be a signal output from the controller 140 and applied to the data line switch SWDL. The data line switch SWDL may be turned on or turned off by the switch control signal Data_Hi-z.

Referring to the diagram illustrating the control signal and voltage waveform for each period in the sensing driving of FIG. 3 , the sensing driving of the display device 100 according to embodiments of the present invention includes an initialization period (Initial), a tracking period (Tracking) and It may include a sensing period (Sensing). In addition, the sensing period Sensing may be divided into a first sensing period Sensing_1 to a fourth sensing period Sensing_4 according to a control signal and a voltage.

4 is a diagram illustrating an exemplary structure of a sub-pixel SP and waveforms of control signals and voltages in an initialization period (Initial) according to embodiments of the present invention.

In the initialization period Initial, the driving voltage EVDD may be applied. The switching transistor SWT and the sensing transistor SENT are connected to the gate line GL, and a gate signal having a turn-on level voltage may be applied to the gate line GL. A data voltage for sensing driving may be applied to the data voltage Vdata during the sensing driving period.

In the initialization period Initial, the sensing driving switch Spre is turned on to apply the sensing driving reference voltage VpreS to the source node N2 of the driving transistor DRT. The controller 140 may output a low-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-on state. The data line switch SWDL is turned on to apply a data voltage for sensing driving to the gate node N1 of the driving transistor DRT.

In the initialization period Initial, the sampling switch SAM may be in a turn-off state.

Accordingly, the data voltage for sensing driving may be applied as a constant voltage to the gate node N1 of the driving transistor, and the reference voltage VpreS for sensing driving may be applied as a constant voltage to the source node N2 of the driving transistor.

In the initialization period Initial, the light emitting device ED is connected to the source node N2 of the driving transistor and the base voltage EVSS, and current flows to emit light.

In addition, in some cases, the starting point of the initialization period (Initial) may be after the driving of the display device 100 is stopped and the power is turned off.

5 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a tracking period.

Referring to FIG. 5 , the driving voltage EVDD may be applied during the tracking period. In addition, a gate signal of a turn-on level voltage may be applied to the switching transistor SWT and the sensing transistor SENT.

The controller 140 may output a low-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-on state. Accordingly, the data line switch SWDL may be maintained in a turned-on state, and a data voltage for sensing driving may be applied to the gate node N1 of the driving transistor DRT.

The sensing driving switch Spre may be turned off. Accordingly, the source node N2 of the driving transistor DRT may be in a floating state, and the voltage may be varied. The voltage Vs of the source node N2 of the driving transistor DRT may increase as the driving voltage EVDD is applied while the voltage Vg of the gate node N1 is constant. In addition, the voltage Vs of the source node N2 may gradually increase and then no longer increase. At this time, it is said that the voltage Vs of the source node N2 is saturated. After the voltage Vs of the source node N2 is saturated, the difference Vgs between the voltage Vg of the gate node N1 of the driving transistor DRT and the voltage Vs of the source node N2 is maintained constant. can be

Referring to FIG. 5 , the voltage of the source node N2 may be saturated when the tracking period ends.

Meanwhile, referring to FIG. 12 , the saturation voltage when the voltage of the source node N2 is saturated may vary depending on the degree of deterioration of the light emitting device ED. Since the threshold voltage of the light emitting element ED increases according to the degree of deterioration of the light emitting element ED, as the deterioration of the light emitting element ED progresses, the level of the voltage saturated at the source node N2 of the driving transistor may increase. have.

Charge may be charged in the storage capacitor Cstg by the difference Vgs between the voltage of the gate node N1 of the driving transistor DRT and the voltage of the source node N2. In the tracking period, the light emitting device ED may emit light.

6 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a first sensing period (Sensing_1).

Referring to FIG. 6 , a driving voltage EVDD may be applied in the first sensing period Sensing_1 , and a gate signal having a turn-on level voltage may be applied to the switching transistor SWT and the sensing transistor SENT. The data driving circuit 120 may output a data voltage for sensing driving.

Referring to FIG. 6 , in the first sensing period Sensing_1 , the data line switch SWDL may be turned off. Accordingly, the gate node N1 of the driving transistor DRT may be in a floating state and a voltage may be varied. The controller 140 may output a high-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-off state.

In the first sensing period Sensing_1 , the sensing driving switch Spre may maintain a turn-off state. Accordingly, the source node N2 of the driving transistor DRT may be in a floating state and the voltage may be varied.

The gate node N1 of the driving transistor DRT is connected to the line capacitor Cline of the sensing line SL, so that the voltage Vs of the gate node N2 decreases, and the amount of charge charged in the line capacitor Cline can increase

In addition, the voltage Vg of the gate node N1 electrically coupled to the source node N2 may also decrease.

7 is an exemplary diagram of a sub-pixel structure according to embodiments of the present invention in a second sensing period Sensing_2, and a diagram illustrating control signals and voltage waveforms.

Referring to FIG. 7 , a driving voltage EVDD may be applied, and a gate signal having a turn-on level voltage may be applied to the switching transistor SWT and the sensing transistor SENT. The data driving circuit 120 may output a data voltage for sensing driving.

In the second sensing period Sensing_2 , the controller 140 may output a high-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-off state. Accordingly, the turn-off state of the data line switch SWDL may be maintained.

In the second sensing period Sensing_2, the sensing driving switch Spre may be turned on. Accordingly, the sensing driving reference voltage VpreS may be applied to the source node N2 of the driving transistor DRT.

Also, referring to FIG. 12 , the gate node N1 of the driving transistor DRT is coupled to the source node N2 , so that the voltage Vg of the gate node N1 is lowered and the voltage of the source node N2 is lowered. (Vs) and may have a constant voltage difference. The degree to which the voltage Vs of the gate node N1 is lowered may vary according to the degree of deterioration of the light emitting device ED.

8 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in a third sensing period (Sensing_3).

Referring to FIG. 8 , a driving voltage EVDD may be applied, and a gate signal having a turn-on level voltage may be applied to the switching transistor SWT and the sensing transistor SENT. The data driving circuit 120 may output a data voltage for sensing driving.

In the third sensing period Sensing_3 , the controller 140 may output a high-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-off state. The data line switch SWDL may be maintained in a turned-off state. Accordingly, the gate node N1 of the driving transistor DRT may be in a floating state and a voltage may be varied.

In the third sensing period Sensing_3, the sensing driving switch Spre may be turned off. Accordingly, the source node N2 of the driving transistor DRT may be in a floating state, and the voltage may be varied.

The voltage of the source node N2 of the driving transistor DRT may increase in a floating state, and in this case, the voltage may increase linearly.

In addition, the voltage of the gate node N1 coupled to the source node N2 may also increase as the voltage of the source node N2 increases.

Meanwhile, the sensing line SL is connected to the source node N2 of the driving transistor, and as the voltage of the source node N2 increases, the amount of charge charged in the line capacitor Cline may increase.

9 is a diagram illustrating an exemplary sub-pixel structure and a control signal and voltage waveform according to embodiments of the present invention in the fourth sensing period (Sensing_4).

Referring to FIG. 9 , a driving voltage EVDD may be applied, and a gate signal having a turn-on level voltage may be applied to the switching transistor SWT and the sensing transistor SENT. The data driving circuit 120 may output a data voltage for sensing driving.

In the fourth sensing period Sensing_4 , the controller 140 may output a high-level switch control signal Data_Hi-z to maintain the data line switch SWDL in a turned-off state. Accordingly, the voltage of the gate node N1 of the driving transistor DRT may be varied in a floating state.

In the fourth sensing period Sensing_4 , the sensing driving switch Spre may maintain a turn-off state. Accordingly, the source node N2 of the driving transistor DRT may be in a floating state, and the voltage may be varied.

Referring to FIG. 9 , while the sampling switch SAM is turned on, it may receive a voltage from the line capacitor Cline and apply the voltage applied to the sensing line SL to the analog-to-digital converter ADC.

The timing at which the sampling switch SAM is turned on may vary according to a design of a person skilled in the art.

Accordingly, the analog-to-digital converter ADC may sense the voltage applied to the sensing line SL.

In addition, according to embodiments of the present invention, the degree of deterioration of the light emitting device ED may be sensed by sensing the voltage of the sensing line SL while increasing the opening area.

10 is an exemplary diagram of a data driving circuit 120 according to embodiments of the present invention.

Referring to FIG. 10 , the data driving circuit 120 according to embodiments of the present invention includes a digital-to-analog converter DAC capable of supplying a data voltage Vdata to a data line DL, and a sensing line SL. It may include a reference voltage output unit 1000 capable of supplying a reference voltage VpreS for sensing driving, and an analog-to-digital converter ADC capable of receiving a voltage of the sensing line SL.

The digital-to-analog converter (DAC) may include a data voltage output unit including the digital-to-analog converter (DAC). The digital-to-analog converter (DAC) may be electrically connected to the controller 140 to receive image data (Data) from the controller 140, convert it into a data voltage (Vdata), and output it to the data line (DL). . During the initialization period Initial to the fourth sensing period Sensing_4 , the timing controller 140 may output a digital value corresponding to the sensing driving data voltage to the digital-to-analog converter DAC. The digital-to-analog converter DAC may output a data voltage for sensing driving to the data line DL.

The reference voltage output unit 1000 may convert a digital value input from the controller 140 into a reference voltage VpreS for sensing driving and supply it to the sensing line SL.

In addition, the data driving circuit 120 according to embodiments of the present invention includes a data line switch SWDL for controlling the output of the data voltage Vdata from the digital-to-analog converter DAC to the data line DL, and a reference voltage. A sensing switch Spre connected between the output unit 1000 and the sensing line SL to control the output of the sensing driving reference voltage VpreS, and the sensing line SL to the analog-to-digital converter ADC A sampling switch (SAM) capable of controlling the voltage supply may be included.

1 and 10 , the data line switch SWDL, the sampling switch SAM, and the sensing switch Spre included in the data driving circuit 120 according to the embodiments of the present invention are configured in the controller 140 . The operation timing may be controlled by the applied data driving circuit control signal DCS. The signal controlling these switches may be any signal among the data driving timing control signals DCS for controlling the operation timing of the data driving circuit 120 .

Accordingly, in the embodiments according to the present invention, it will be possible to introduce the voltage sensing method used in the existing two-scan structure in order to sense the degree of deterioration of the light emitting device ED and compensate for the deterioration even under the one-scan structure. can

That is, according to the embodiments of the present invention, the degree of deterioration of the light emitting device ED may be sensed and the deterioration may be compensated for by using a voltage sensing method instead of a current sensing method while adopting a one-scan structure.

Accordingly, it is possible to sense the degree of deterioration of the light emitting device ED without using a current sensing method using an integrator, which is advantageous in terms of cost reduction.

Accordingly, according to embodiments of the present invention, the display device 100 capable of sensing the deterioration degree of the light emitting element ED and compensating for deterioration in a one-scan structure without including an integrator in the data driving circuit 120 . can provide

11 is a diagram illustrating a sensing operation step by step according to embodiments of the present invention.

Referring to FIG. 11, sensing driving according to embodiments of the present invention may include an initialization step (S1110), a tracking step (S1120), and a sensing step (S1130 to S1160). , the sensing step may again include a first sensing step (S1130), a second sensing step (S1140), a third sensing step (S1150), and a fourth sensing step (S1160).

Referring to FIG. 11 , in the initialization step S1110 , the data line switch SWDL is turned on, the sensing switch Spre is turned on, and the gate node N1 of the driving transistor DRT is A constant voltage may be applied to each of the source nodes N2 . The voltage applied to the gate node N1 may be a data voltage for sensing driving. The voltage applied to the source node N2 may be a sensing driving reference voltage VpreS.

In the tracking step S1120 , the data line switch SWDL maintains a turned-on state, and the sensing switch Spre is turned off, and a constant voltage is applied to the gate node N1 of the driving transistor DRT. and the voltage of the source node N2 may be varied. The voltage Vs of the source node N2 may increase. In this case, the voltage Vs of the source node N2 may be saturated at a higher voltage according to the degree of deterioration of the light emitting device ED.

In the first sensing step S1130 , the data line switch SWDL is turned off, the sensing switch Spre maintains a turned-off state, and the voltage Vs of the source node N2 of the driving transistor DRT is As this becomes lower, the voltage of the gate node N1 coupled to the source node N2 may also be lowered.

In the second sensing step S1140 , the data line switch SWDL maintains a turned-off state, the sensing switch Spre is turned on, and a sensing driving reference voltage VpreS is applied to the source node N2 . can be Accordingly, the voltage Vs of the source node N2 may have a constant value, and the voltage of the gate node N1 coupled to the source node N2 may also have a constant value.

In the third sensing step S1150 , the data line switch SWDL maintains a turned-off state, the sensing switch Spre is turned off, and the voltage Vs of the source node N2 of the driving transistor DRT. The value can be large. The voltage of the gate node N1 coupled to the source node N2 may also increase. As the voltage of the source node N2 increases, the voltage applied to the sensing line SL electrically connected to the source node N2 may also increase.

In the fourth sensing step S1160, the data line switch SWDL maintains a turn-off state, the sensing switch Spre maintains a turn-off state, the sampling switch SAM is turned on, and the analog digital The voltage of the sensing line SL may be applied to the converter ADC.

Accordingly, embodiments according to the present invention can provide the display device 100 using the inexpensive data driving circuit 120 while increasing the opening area.

12 is a diagram illustrating control signals and voltage waveforms for each period for sensing the degree of deterioration of the light emitting device ED according to embodiments of the present invention.

3 and 12 , the light emitting device ED emits light according to a voltage between the gate node N1 and the source node N2 of the driving transistor DRT. When the driving transistor DRT and the light emitting device ED are expressed on an equivalent circuit, the driving transistor DRT and the light emitting device ED may be expressed as resistance components, respectively. In addition, the voltage Vs of the source node N2 node of the driving transistor DRT is divided by the voltage of the first resistance component R1 of the driving transistor DRT and the second resistance component R2 of the light emitting device ED. It can be determined by law.

When the light emitting element ED is deteriorated, a resistance component of the light emitting element increases. Accordingly, it can be said that the second resistance R2 increases if expressed on an equivalent circuit. Since the current Ids between the drain node and the source node of the driving transistor DRT decreases due to the deterioration of the light emitting device ED, the voltage between the gate node N1 and the source node N2 of the driving transistor DRT is Compared with before deterioration, it becomes small after deterioration.

Accordingly, the amount of charge stored in the line capacitor Cline of the sensing line SL is also charged to a small value according to the degree of deterioration. The slope of the amount of charge charged in the line capacitor Cline according to the degree of degradation per unit time may decrease as the degree of degradation of the light emitting device ED increases.

Therefore, even if the sampling switch SAM is turned on with a predetermined time interval from the point at which the sensing switch Spre is turned off, for example, depending on the degree of deterioration of the light emitting element ED, the line capacitor Cline ), the magnitude of the voltage applied to the sensing line SL may vary. Accordingly, a voltage value applied to the analog-to-digital converter (ADC) may vary.

That is, the voltage sensed by the analog-to-digital converter ADC may be a voltage value reflecting the degree of deterioration of the light emitting device ED. For example, the voltage value sensed by the analog-to-digital converter ADC may decrease as the deterioration of the light emitting element ED increases.

The analog-to-digital converter (ADC) included in the display device 100 according to the embodiments of the present invention converts the voltage of the sensing line SL into a digital value, and converts the sensed data (sensing value), which is the converted digital value, to the controller ( 140) can be transmitted.

The controller 140 receives the sensing data, detects deterioration of the light emitting device ED based on the sensed data, calculates a compensation value for compensating for deterioration deviation between the light emitting devices ED based on this, and stores it in the memory. .

The controller 140 may change the image data to be supplied to the corresponding sub-pixel SP based on the compensation value stored in the memory and supply it to the data driving circuit 120 . Accordingly, the data driving circuit 120 may convert the changed image data Data' into a data voltage Vdata' in the form of an analog voltage and output it to a corresponding data line. Accordingly, deterioration compensation of the light emitting device ED in the corresponding sub-pixel SP may be actually performed.

Here, the deterioration of the light emitting element ED may mean a threshold voltage of the light emitting element ED, and the deterioration deviation between the light emitting elements ED may mean a threshold voltage deviation between the light emitting elements ED. .

Accordingly, in the display device 100 according to the exemplary embodiments of the present invention, it is possible to compensate the characteristic value of the light emitting device ED without adding an integrator to the data driving circuit 120 in the one scan structure. Accordingly, it is possible to provide the display device 100 having a large opening area, realizing high luminance, and having a low manufacturing cost of the data driving circuit 120 .

In addition, the display device 100 according to embodiments of the present invention compensates for deterioration of the light emitting device ED, thereby improving the problem of an afterimage remaining when the display device 100 is driven for a long time.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. In addition, since the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: display device
110: display panel
120: data driving circuit
130: gate driving circuit
140: controller
1000: reference voltage output unit

Claims (12)

In the display device,
a display panel including a plurality of data lines, a plurality of gate lines, and a plurality of sub-pixels including a light emitting device;
a data driving circuit for driving the plurality of data lines; and
a gate driving circuit for driving the plurality of gate lines;
Each of the plurality of sub-pixels,
a driving transistor for driving the light emitting device;
a switching transistor controlled by a gate signal and controlling a connection between a first node of the driving transistor and a corresponding data line;
a sensing transistor controlled by the gate signal and controlling a connection between a second node of the driving transistor and a corresponding sensing line; and
a storage capacitor electrically connected between a first node and a second node of the driving transistor;
The display device is
a first switch for controlling a connection between a data voltage output node to which a data voltage is output in the data driving circuit and the data line;
a second switch for supplying a sensing driving reference voltage to the second node;
an analog-to-digital converter for sensing the voltage of the sensing line; and
Further comprising a third switch for controlling an electrical connection between the sensing line and the analog-to-digital converter,
When the first switch is in a turn-on state, a sensing driving data voltage is applied to the first node, and when the first switch is in a turn-off state, the voltage of the first node varies;
When the second switch is in a turn-on state, a sensing driving reference voltage is applied to the second node, and when the second switch is in a turn-off state, the voltage of the second node fluctuates;
In a period in which the first switch and the second switch are turned off and the voltage of the first node is increased, the third switch is turned on, and the analog-to-digital converter senses the voltage of the sensing line. display device.
According to claim 1,
during the first period,
The first switch and the second switch are turned on,
A display device in which a sensing driving data voltage is applied to the first node and a sensing driving reference voltage is applied to the second node.
3. The method of claim 2,
for a second period after the first period,
The first switch maintains a turned-on state, and the second switch is turned off,
A data voltage for sensing driving is applied to the first node, and a voltage is increased to the second node.
4. The method of claim 3,
for a third period after the second period,
The first switch is turned off, the second switch maintains a turned-off state, and the voltages of the first node and the second node decrease at the same time,
for a fourth period after the third period,
The first switch maintains a turned-off state, the second switch is turned on, the sensing driving reference voltage is again applied to the second node, and the voltage of the first node is applied to the second node changes by the amount of voltage fluctuation of
for a fifth period after the fourth period,
A display device in which the first switch maintains a turned-off state, the second switch is turned off, and voltages of the first node and the second node increase simultaneously.
5. The method of claim 4,
after the fifth period,
The third switch is turned on, and the analog-to-digital converter senses the voltage of the sensing line.
According to claim 1,
In the period from when the gate signal of the turn-on level voltage period is applied to the switching transistor and the sensing transistor until the gate signal of the turn-off level voltage period is applied to the switching transistor and the sensing transistor,
A data voltage for sensing driving is applied to the first node, or the voltage of the first node is changed;
A display device in which a sensing driving reference voltage is applied to the second node or a voltage of the second node is varied.
According to claim 1,
Further comprising a line capacitor electrically connected to the sensing line,
The line capacitor is
A display device in which the sensing driving reference voltage is applied to the second node again and is charged during a period in which the first switch and the second switch are turned off.
A method of driving a display device, comprising:
The display device is
a display panel including a plurality of data lines, a plurality of gate lines, and a plurality of sub-pixels including a light emitting device;
a data driving circuit for driving the plurality of data lines; and
a gate driving circuit for driving the plurality of gate lines;
Each of the plurality of sub-pixels,
a driving transistor for driving the light emitting device;
a switching transistor controlled by a gate signal and controlling a connection between a first node of the driving transistor and a corresponding data line;
a sensing transistor controlled by the gate signal and controlling a connection between a second node of the driving transistor and a corresponding sensing line; and
a storage capacitor electrically connected between a first node and a second node of the driving transistor;
The display device is
a first switch for controlling a connection between a data voltage output node to which a data voltage is output in the data driving circuit and the data line;
a second switch for supplying a sensing driving reference voltage to the second node;
an analog-to-digital converter for sensing the voltage of the sensing line; and
Further comprising a third switch for controlling an electrical connection between the sensing line and the analog-to-digital converter,
When the first switch is in a turn-on state, a sensing driving data voltage is applied to the first node, and when the first switch is in a turn-off state, the voltage of the first node varies;
When the second switch is in a turn-on state, a sensing driving reference voltage is applied to the second node, and when the second switch is in a turn-off state, the voltage of the second node fluctuates;
In a period in which the first switch and the second switch are turned off and the voltage of the first node is increased, the third switch is turned on, and the analog-to-digital converter senses the voltage of the sensing line. In the method of driving a display device,
Driving the display device,
turning on the first switch and the second switch, applying a sensing driving data voltage to the first node, and applying a sensing driving reference voltage to the second node;
maintaining the first switch in a turned-on state, turning the second switch off, applying a sensing driving data voltage to the first node, and increasing the voltage of the second node;
turning off the first switch, maintaining the second switch in a turned-off state, and lowering voltages of the first node and the second node;
maintaining the first switch in a turned-off state, turning the second switch on, and applying a sensing driving reference voltage to the second node again;
maintaining the first switch in a turned-off state, turning the second switch off, and simultaneously increasing the voltage of the first node and the voltage of the second node;
and the third switch is turned on and the analog-to-digital converter senses the voltage of the sensing line.
9. The method of claim 8,
During a period in which a gate signal of a turn-on level voltage section is applied to the switching transistor and the sensing transistor,
The third switch is turned on, and the analog-to-digital converter senses the voltage of the sensing line.
a data voltage output unit outputting a data voltage to the data line;
a reference voltage output unit for outputting a reference voltage for sensing driving to the sensing line;
a voltage sensing unit connected to the sensing line to sense a voltage of the sensing line;
a first switch connected to a data voltage output node of the data voltage output unit to control an output of a data voltage for sensing driving to the data line;
a second switch connected to a reference voltage output node for sensing driving of the reference voltage output unit to control an output of the reference voltage for sensing driving; and
a third switch connected to a voltage input node of the voltage sensing unit to control input of a voltage of the sensing line to the voltage sensing unit;
a first period in which the first switch is turned on to output a sensing driving data voltage, and the second switch is turned on to output a sensing driving reference voltage;
a second period in which the first switch maintains a turn-on state after the first period, a sensing driving data voltage is output, and the second switch is turned off;
a third period in which the first switch is turned off and the second switch maintains a turned-off state after the second period;
a fourth period in which the first switch maintains a turn-off state and the second switch is turned on to output a sensing driving reference voltage after the third period;
a fifth period in which the first switch maintains a turn-off state and the second switch maintains a turn-off state after the fourth period;
After the fifth period, the third switch is turned on and the voltage sensing unit receives the voltage of the sensing line.
11. The method of claim 10,
The data driving circuit is
Electrically connected to a controller for controlling the first switch, the second switch, and the third switch,
The timing at which the first switch, the second switch, and the third switch are turned on and turned off is controlled by a control signal output from the controller.
In the display device,
a display panel including a plurality of data lines, a plurality of scan lines, and a plurality of sub-pixels including a light emitting device;
a data driving circuit for driving the plurality of data lines; and
a gate driving circuit for driving the plurality of gate lines;
Each of the plurality of sub-pixels,
a driving transistor for driving the light emitting device;
a switching transistor controlled by a gate signal and controlling a connection between a first node of the driving transistor and a corresponding data line;
a sensing transistor controlled by the gate signal and controlling a connection between a second node of the driving transistor and a corresponding sensing line; and
a storage capacitor electrically connected between a first node and a second node of the driving transistor;
When the data line is in a low impedance state, a sensing driving data voltage is applied to the first node, and when the data line is in a high impedance state, the voltage of the first node varies;
When the impedance of the data line is greater than or equal to a predefined threshold, the data line is in the high-impedance state, and when the impedance of the data line is less than the threshold, the data line is in the low-impedance state;
When the sensing driving reference voltage is supplied to the sensing line, the sensing driving reference voltage is applied to the second node, and when the supply of the sensing driving reference voltage to the sensing line is cut off, the second The voltage at the node fluctuates,
A period in which the data line is in a low impedance state includes a period in which the light emitting element emits light, and a period in which the data line is in a high impedance state includes a period in which the light emitting element does not emit light.

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